Got the NEW Maglite ML25IT 2C

fivemega

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A 5 cell bulb will work if you have let batteries rest a little while and the combo has settled down to 7.4 volts.

But lithium ion batteries don't settle. If they go below 4.2v after charging, they're getting bad.

My Nitecore RCR's come off the charger at 4.2 to 4.3. After setting over night they are at 3.7 to 3.8

Lithium ion battery should go no less than 2.5 volt and no more than 4.25. After fully recharge, they are about 4.2 volt.
If a fully recharged cell after resting has 3.7 volt which is about 25% energy left, then it's time to replace or something is wrong.
A good and fully recharged Lithium ion battery should go no less than 4 volt after sitting a month.
A 6 volt (5 cell) Xenon bulb with life of 40 hours will flash with regulated and fixed 7.4 volt. Let alone 8 or 8.4 volts.
If anybody drive this setup with no problem, there is definitely some voltage drop on batteries, switch, connections and ....
 

InvisibleFrodo

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Woah, what? Coming off the charger at 4.3 is something I wouldn’t do if I could help it. In my experience cells do still settle because any charger running constant voltage mode will still have a minimum current. For example 0.03 amps. Once that current cuts off, the cells voltage settles. But in my experience they’ll settle to something like 4.17 relatively quickly. Down to maybe 4.12 within a few days. Going down to 3.7 or 3.8 overnight is weird.
I got a new malkoff MD4 with M61W and for now I’m powering it with an old pair of red labeled AW Li-MN 2200 mah 18650s. They’re AW’s, they’re pretty old. After charging them and using them on a long walk with my little girl as well as “playing” with it at work and outdoors alone, those cells are at 3.87.
Mr. Fixer, your lithium’s should really be holding voltage better. Something is amiss…
Even my LiPo4 experience is that they settle to 3.4 on their own. Then they flatline at 3.35 for almost the entire discharge, then by the time they’re at 3.32 or 3.3, they are dead.
I do most all of this on an old Duratrax intellipeak ICE. Still a good charger.
 

bykfixer

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I'm prrrrrretty sure that's what my batteries do using a NiteCore D4 charger folks.
I stick 'em on the charger, let 'em charge until the readout says full and set 'em aside since I mainly use primary batteries. The batteries for ML25IT lights get charged a couple times a year (as they are not in my rotation anymore) and my NiteCore RCR's when the low voltage circuit kicks in or each season whichever comes first.
 

vicv

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We're not disagreeing that's how it's working for you Mr. Fixer. We're saying it's bad. Li ion batteries don't self discharge. At 3.7v open circuit they're practically dead. Something is wrong with either your batteries or your measuring equipment
 

bykfixer

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I'll charge the RCR I use in my daily this evening and see what it does. Then I'll stick it back on the charger in the morning and see what it reads.
Next time I charge the Nuon's I'll do same. See, I don't read the voltage the next day. I've just always let them rest over night. Perhaps they do what you guys say and based on things I've read here just assumed they dropped that much.
 
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Olumin

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Lithium ion battery should go no less than 2.5 volt and no more than 4.25. After fully recharge, they are about 4.2 volt.
If a fully recharged cell after resting has 3.7 volt which is about 25% energy left, then it's time to replace or something is wrong.
A good and fully recharged Lithium ion battery should go no less than 4 volt after sitting a month.
A 6 volt (5 cell) Xenon bulb with life of 40 hours will flash with regulated and fixed 7.4 volt. Let alone 8 or 8.4 volts.
If anybody drive this setup with no problem, there is definitely some voltage drop on batteries, switch, connections and ....

Why is a 5 cell xenon bulb 6 volts when 1,5 x 5 equals 7,5 volts? At most it will be overdriven by 0,9 volts by two freshly charged Li-ions. Will that really blow the bulb? A 6 cell xenon would be severely underdriven by that measure (9V/7,4V), I can’t imagine that being good for the bulb either? What am I missing?
 

vicv

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Alkalines are more like 1.1-1.2 v a cell at 1A. A pair of good 18650s will be 3.9v-4v under a 1A load each.
 
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Olumin

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Im not great at DIY electrics/electronics, maybe thats why I picked up watchmaking. You rarely do anything more then change a battery on quartz models, and when something is broken, you swap out the whole movement (not hat it would be worth it to repair anything in most cases anyway, or even possible).

That would mean however that even a 6 cell bulb would still be overdriven by 1,2v by two fresh li-ions. Would that still blow?
 

vicv

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No. 6 alkalines would be roughly 7.2v and drop quickly. 2x 18650 would be ~7.7-7.8v and dropping slowly. The bulb can handle the extra voltage. It's not much. Also mag bulbs are generally quite robust so they can handle some extra. The older pr bulbs could handle a lot more. I'm running a 5 cell with 2 18650s and it works well. But these bi-pin bulbs are designed to burn hotter/whiter so they have less overdrive capability.
So it all depends on the bulb. I have a light that runs on 3x18650s and I've installed a 6v 2000hr bulb in it. It's being driver at triple the designed wattage. But because it's a 2000hr bulb, it can handle the extra 5v. For a while.
 

Olumin

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I see, thank you. In that case I will try a 6 cell mag-star with two 26500s and see how that works out. Are there currently any 26500s available with more then 3000mAh? No experience with this battery. The ones I see popping up are from Efest.
 

xxo

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26500's are probably too fat unless they are a little under 26 mm dia. 2 protected 21700's should fit perfect in a 3C ML25IT.
 

Olumin

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26500's are probably too fat unless they are a little under 26 mm dia. 2 protected 21700's should fit perfect in a 3C ML25IT.

Im running a 2c. My calipers measure battery tube diameter to be 26,6mm. Cell diameter is given as 26,26 +/- 0,1mm. Should fit. But I hadn't even considered running two 21700s in a 3c. Might try that. That should give me what, about 1 Hour of runtime with a 6 cell Mag-star bulb?
 

xxo

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Im running a 2c. My calipers measure battery tube diameter to be 26,6mm. Cell diameter is given as 26,26 +/- 0,1mm. Should fit. But I hadn't even considered running two 21700s in a 3c. Might try that. That should give me what, about 1 Hour of runtime with a 6 cell Mag-star bulb?


Should run longer on 5Ah 21700's. If I remember right, the 6 cell xenon Mag bulbs only draw a little over an Amp.

BTW, The best Mag bulbs were the old PR xenons. though they are getting hard to find and won't fit in unmodified ML25's.
 

vicv

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Ya more like 4-5 h runtime before noticable dimming. And about 180 lumens. It's perfect. It is in an old 3c anyway. I'm sure in the smaller ml it'll be even better
 
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xxo

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Ya more like 4-5 h runtime before noticable dimming. And about 180 lumens. It's perfect. It is in an old 3c anyway. I'm sure in the smaller ml it'll be even better


I have a ordinary 3C Mag (not the ML25IT) set up to run a 6 cell xenon and a couple of keep power 21700's, but I have not tested the run time but it works real well.
 

Olumin

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Ah ok wow, didn’t expect that considering the output. I think I’m gonna stick with modifying my 2C for now, since I don’t currently have a 3C lying around. I also don’t have another light that takes 21700s, so buying those batteries just for that doasnt really make sense. Ill report back how it goes.
 

Olumin

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Well thats about 2000 vs 3000mAh for the 26500s, and according to my measurements it should fit. Akkuteile.de usually gives very accurate measurements so I trust them in this regard. Ill just try it with the 26s and see how that goes.
 
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